Vertigo is caused by vestibular disturbance and is the result of:
- Intrinsic labyrinthine diseases – Meniere’s disease, benign paroxysmal positional vertigo and acute vestibular failure
- Spread of disease from an infected middle ear to the labyrinth
- Disease in the brainstem or cerebellum
- General systemic conditions affecting the vestibular system
Vertigo, by definition, is an illusion of movement, of the patient or the surroundings. The origin of the name suggests a sense of rotational movement, but should apply to any direction of movement experienced. Imbalance always accompanies vertigo, but is not always due to vertigo and is not a synonym. Imbalance occurs for many reasons without vertigo.
Normal balance needs:
- accurate sensory information from the eyes, proprioceptive receptors and the vestibular labyrinth with coordination of this information within the brain
- normal motor neural control by the central nervous system of an intact musculoskeletal system: normal muscles and joints (Figure 1).
Figure 1 Sensory and motor components of balance
Defects in any of these impair balance – with or without vertigo.
Vertigo arises if information from vestibular sources conflicts with data from the other sensory systems, or when a disordered central integration system in the brain does not correctly relate the body’s movements to the vestibular input. Vertigo is always a symptom of vestibular defect. This may lie in the labyrinth (peripheral) or in its connections within the brain (central). When severe, it is accompanied by nausea and vomiting.
Vertigo is caused by:
- peripheral vestibular disorders (labyrinthine);
- middle ear infections spreading to the labyrinth;
- central vestibular disorders, such as multiple sclerosis, tumours, infarcts; and
- external damage to the vestibular system – trauma, drugs, anoxia, anaemia, hypoglycaemia, hypotension or viral infections (Bullet list 1).
Bullet list 1 Origins of vertigo
- Peripheral (labyrinthine)
- Central: In the brain (brainstem, cerebellum or higher)
The commonest peripheral vestibular disorders (labyrinthine) are Meniere’s disease and other forms of endolymphatic hydrops, benign paroxysmal positional vertigo, sudden vestibular failure and vascular disturbances (Bullet list 1).
Bullet list 2 Peripheral (labyrinthine) disorders
- Meniere’s disease
- Benign paroxysmal peripheral vertigo (BPPV)
- Sudden vestibular failure
Bullet list 3 Duration of vertigo
- Meniere’s disease: hours
- Benign paroxysmal positional vertigo: seconds only
- Sudden vestibular failure: days
Meniere’s disease (idiopathic endolymphatic hydrops)
This is a disorder of endolymph control, associated with dilatation of the endolymphatic spaces of the membranous labyrinth (hydrops). This dilatation, or endolymphatic hydrops (Figure 2), may be caused by disorders of the otic capsule, but in Meniere’s disease it is, by definition, idiopathic.
Figure 2 Meniere's Disease Cochlear Cross-Section *Note the displacement of the vestibular membrane due to the overabundance of endolymph in scala media
The disease usually affects only one ear, first producing symptoms between the ages of 30 and 60 years. It is characterised by attacks of violent paroxysmal vertigo, often rotatory, associated with deafness and tinnitus. Attacks occur in clusters with periods of remission, during which balance is normal. Each lasts for several hours, rarely less than 10 minutes or more than 12 hours (Bullet list 2), and is accompanied by prostration, nausea and vomiting. A sensation of pressure in the ear, increase or change in the character of tinnitus, pain in the neck or increased deafness often precedes an attack.
The accompanying deafness is sensorineural and fluctuates noticeably in severity. It is associated with distortion of speech and musical sounds, and with severe discomfort on exposure to loud noise (hyperacusis). Hearing loss may precede the first attack, although both symptoms may first arise together. The vertigo may be so catastrophic that hearing loss is not noticed. Hearing improves during remission, but gradually deteriorates persistently, until its impairment becomes severe. The tinnitus is roaring, low-pitched and worse when hearing is most impaired.
At least 20–30% of patients have disease in both ears. The prevalence of bilateral disease varies widely in reports from different centres, with implications for treatment, and deafness then tends to become more worrying than the vertigo. A variant known as vestibular hydrops produces attacks of episodic vertigo without any auditory symptoms.
Another variant of Meniere’s disease is cochlear hydrops, which is a very common cause of fluctuating hearing loss with tinnitus and distortion, but without vertigo. This common complaint may often be ascribed incorrectly to Eustachian tube obstruction.
Similar vestibular vertigo may be secondary to total cochlear hearing loss from any cause. It may occur after many years, when the deafness has arisen congenitally, after mumps viral infection or head trauma.
Treatment of Meniere’s disease
Medical treatment is usually chosen from an armamentarium including histamine agonists such as Betahistine (Serc), often used in the UK as a first choice (but not in the USA, since the FDA consider evidence of efficacy to be insufficient), vasodilator drugs such as nicotinic acid in a dose sufficient to cause flushing, diuretics combined with a sodium-restricted diet and corticosteroids. These treatments may need symptomatic support with antivertigo drugs. This wide range of medication is testimony to our continuing uncertainty about the underlying causes of this disorder.
Operative treatment should be considered if the symptoms are not adequately controlled by medication. Conservative surgical procedures aim to protect hearing, and include decompression of the endolymphatic sac (with or without drainage) and selective division of the vestibular branch of the vestibulocochlear nerve (vestibular neurectomy). Labyrinthectomy, with total destruction of the membranous labyrinth, almost guarantees relief from the vertigo but at the expense of total loss of hearing in that ear. This is often acceptable if the hearing remains only as a painful distorted shred in the affected ear when the other is normal, even though the possible risk of developing disease in the other ear cannot be discounted.
Benign paroxysmal positional vertigo (BPPV)
Benign paroxysmal positional vertigo (BPPV) is the commonest cause of vertigo (Bullet list 4 for features of BPPV). It is provoked by movements of the head usually to one side when turning in bed or on looking upwards and caused by debry (otocania) in the semi-circular canals (Figure 3), . Each attack is violent yet lasts for only a few seconds, and only occurs on assuming the provoking position of the head. There are no auditory symptoms. Episodes usually abate and disappear within a few weeks or months, but they often recur.
Figure 3 Benign paroxysmal positional vertigo - Gif of otocania (debry) in semi-circular canals of the ear.
Bullet list 4 Features of BPPV
Features of nystagmus in BPPV on positional testing:
- Rotator beating underlying ear
- Latent period of several seconds before onset
- Abatement after 5–20 s with reduction on repeat testing
- No change in direction while testing
The disorder is caused by detachment of otoconia (calcium carbonate crystals) from the otolith organ of the utricle. They fall into the posterior semicircular canal and distort its cupula when the head is put into the provoking underlying position. Both labyrinths may be affected. Causes may be mechanical in head injury, viral infections or degenerative changes with ageing. Usually there is no recognisable explanation.
Treatment of benign paroxysmal positional vertigo
Most patients need no more than reassurance and avoidance of the provoking head position until recovery. Medication has no useful place. So-called ‘repositioning’ manoeuvres, involve head movement through a precise sequence of positions designed to force the displaced otoconia out of the posterior canal into the vestibule, and are effective. They are best carried out by experienced people in audiology or neuro-otology units. Some patients may be helped by exercises that deliberately provoke the vertigo, to encourage central compensation for the abnormal vestibular stimuli, but few agree to this unpleasant experience.
Above: Figure 4 Epley's manuevre which is used to treat BPPV
Diagnosis is based on eliciting the history of head movement provocation and the brevity of the attacks if the position is maintained. Patients often offer misleading accounts of duration for much longer periods, if they have been repeatedly afflicted over many hours.
Operative measures, which are only used for rare, persistent, severe symptoms, include division of the nerve to the posterior semicircular canal ampulla (singular neurectomy), and obliteration of the lumen of the posterior semicircular canal.
Sudden vestibular failure
Sudden vestibular failure (Figure 8.4) occurs when one peripheral labyrinth suddenly stops working. This may happen for many reasons – head injuries, viral infection, blockage of an end artery supplying the labyrinth, multiple sclerosis, diabetic neuropathy or brainstem encephalitis. It is sometimes confusingly referred to as vestibular neuronitis, or ‘labyrinthitis’. These labels are better avoided. The symptoms are sudden vertigo with prostration, nausea and vomiting.
There are no auditory features, and the vertigo persists continuously, gradually improving over many days or weeks. Head movements exacerbate vertigo, but after a few days it may cease unless the head is moved. Patients gradually regain balance so that, on the third or fourth day after onset, they may move unsteadily around the room, holding on to objects for support. By the end of 10 days, unsupported walking becomes possible. After 3 weeks gait may seem normal, but patients still feel insecure, particularly in the dark or when tired.
Recovery is slower and less complete in the elderly. It relies on compensating changes within the brain, and imbalance may return temporarily whenever the acquired compensation breaks down, for example through defects in other sensory systems, fatigue, other illnesses, drugs or the cerebral degeneration of old age.
Migraine is a common vascular cause of vertigo and may cause symptoms indistinguishable from vertigo. Basilar migraine, affecting teenage girls in the main, is also similar, but may be preceded by posterior cerebral arterial symptoms with disturbance of vision, and may be accompanied by dysarthria and tingling in the hands and feet. Head injury deserves separate mention. Vertigo often follows concussion and, as mentioned above, BPPV may follow. Perilymph fistula, in which perilymph leaks from the vestibule into the middle ear, may be recognised and treated only by otological referral.
Assessment and diagnosis
The first task is to recognise the symptom as vertigo, and then to determine whether there is any systemic cause or extralabyrinthine disorder needing urgent investigation – destructive middle ear dis-
Figure 5 Attic crust may obscure cholesteatoma, a disorder needing urgent investigation
The history is especially important to make sure that the complaint is that of a sense of movement. Duration is of paramount importance (Bullet list 3), but not easily or reliably attained.
Clinical examination should include assessment of the cardiovascular and central nervous systems. Careful examination of the ears is the only way to recognize destructive middle ear disease by cholesteatoma. Exclusion demands that each tympanic membrane be found to be normal. A waxy crust over the pars flaccida is deceptive, as it may cork the entrance to an attic cholesteatoma (Figure 5). If in any doubt, referral for examination with a microscope is essential and anaesthesia may be needed.
Spontaneous jerk nystagmus is always a sign of vestibular disease and is described by the direction of its fast movement. Degree is designated depending on whether it is elicited only with gaze in the direction of the quick beat (1st degree); gazing straight ahead as well (2nd degree); or in all directions (3rd degree). This assessment requires examination of the eyes with good illumination. Inspect in all positions of gaze – but the eyes should not be abducted more than about 30 degrees – until the edge of the iris reaches the caruncle. Certain characteristics of a jerk nystagmus indicate a central cause within the brain.
- nystagmus persisting for more than a few weeks;
- change in the direction of beat (defined by its quick component) either with time or change in direction of gaze;
- beating in directions other than horizontally (e.g. vertically);
- different jerks in the two eyes (ataxic).
Stance and gait are examined clinically by watching the patient stand on both and then each leg alone with the eyes closed, and while walking heel to toe.
Simple positional testing is the essential diagnostic indicator of BPPV. Seated on a couch, the patient turns the head towards the examiner and is told to keep the eyes open, while watching the examiner’s forehead. The tester holds the patient’s head, and lays it rapidly laid backward into a supine position with the head over the edge of the couch at 30 below horizontal (Figure 6). The patient is held in that position for at least 30 seconds, despite protestation, while the eyes are watched for nystagmus. The test is then repeated with the head turned to the other side. Nystagmus provoked by this manoeuvre is always abnormal.
Figure 6 Positional test for vertigo
BPPV is always recognisable by this test, but positional testing can also, very rarely, suggest a vestibular lesion somewhere within the posterior cranial fossa. In BPPV, the nystagmus invariably shows the following features:
- it is rotatory, beating towards the underlying ear;
- a latent period of some seconds precedes its onset;
- it abates after 5–20 s held in the provoking position and is less violent on repeated testing;
- it is accompanied by violent vertigo;
- it does not change direction during observation.
Deviation from even one of these features should suggest a more serious central cause requiring further investigation, preferably by MRI scan.
Neuro-otological investigations of vestibular function
Many tests are available for full assessment. They start with detailed assessment of auditory function, by pure tone audiometry in a soundproofed room, and include recording of brainstem evoked responses to auditory stimuli, which are valuable for recognisingretrocochlear hearing losses that may be caused by vestibular schwannomas (acoustic neuromas).
Vestibular function is assessed by many tests including the Fitzgerald–Hallpike caloric test, in which each lateral semicircular canal is vicariously stimulated by irrigation of the ears with water at temperatures above and below body temperature (30 and 44 ◦ C). Ice-cold water may be used for an apparently ‘dead’ labyrinth. Rotation tests, when the whole body is turned in a specially designed chair, at variable angular acceleration induce nystagmus, which is recorded by electronystagmography. These proffer valuable diagnostic information about both spontaneous and induced nystagmus. Posturography offers ways to assess body position under different external stimuli.
Bullet list 5 Features of central nystagmus
Central spontaneous nystagmus is indicated by:
- Persistence for several weeks
- Change in direction (of quick component) with time or direction of gaze
- Direction other than horizontal
- Ataxic beating
Symptomatic treatment of vertigo
Symptoms may be relieved by sedatives such as prochlorperazine, cinnarizine and other antihistamines. Diazepam is also useful. In a severe attack such as after vestibular failure, bedrest will be necessary whatever the cause. Drugs may be given intramuscularly or as suppositories. Once the acute stage is over, sedatives are continued in small doses for several weeks or months.
If vestibular deficit – rather than irritation of a labyrinthine system – is pronounced, vestibular sedatives may exacerbate the symptoms. This often happens in the degenerative changes of old age, in bilateral Meni`ere’s disease or after ototoxic drug damage. Graded head and eye movement exercises, designed to accelerate the process of central compensation, can help patients. These ‘‘head exercises’’ should be taught and supervised by specially trained physiotherapists.
Other treatment is directed at identified causes, including surgical exploration of any middle ear in which cholesteatomatous erosion of the middle ear is suspected.
Ludman H, Wright T (eds) Diseases of the Ear, 6th edn. Arnold-Hodder, London, 1998.
Luxon LM (ed.) Textbook of Audiological Medicine. Taylor & Francis, London, 2003.